Whether you’re running, swimming, cycling or hula hooping, we have always been told that doing regular exercise will improve our bodies and is one of the keys to a healthy and happy life. Our one-size-fits-all approach to maintaining an active, healthy lifestyle is very rarely questioned, but with recent advances in genetic testing technology and brain stimulation techniques, scientists are uncovering the new and surprising truths about what exercise is really doing to our bodies, and why we all respond to it differently. In this program, Michael Mosley uses himself as a human guinea pig to discover the truth about exercise.